Selective oxidation of phosphorus ylides by dimethyldioxirane. Application to the formation of vicinal tricarbonyls

Dimethyldioxirane (DMD) has proven to be an effective reagent for the selective conversion of phosphoranylidene intermediates 4 to the corresponding vicinal tricarbonyls 5. Unlike existing oxidation protocols which employ relatively vigorous conditions, this transformation is conducted rapidly at low temperature under neutral conditions, without the necessity of an aqueous workup. Selective oxidation of the phosphorus ylides in the presence of a variety of sensitive functionality was achieved by lowering the reaction temperature and controlling the concentration of oxidant.